Path: utzoo!utgpu!news-server.csri.toronto.edu!rutgers!usc!zaphod.mps.ohio-state.edu!math.lsa.umich.edu!hyc
From: hyc@math.lsa.umich.edu (Howard Chu)
Newsgroups: comp.sys.atari.st
Subject: Re: break
Keywords: RTX job control vi ksh csh SIGSTOP _main cli isr
Message-ID: <11916@stag.math.lsa.umich.edu>
Date: 6 May 90 01:18:25 GMT
References: <3060@ultb.isc.rit.edu>
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Reply-To: hyc@math.lsa.umich.edu (Howard Chu)
Organization: University of Michigan Math Dept., Ann Arbor
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In article <3060@ultb.isc.rit.edu> jdb9608@ultb.isc.rit.edu (J.D. Beutel) writes:
>
>Does anybody know how break (i.e., ^C) works on the ST?
>Is it something in TOS?  (I wouldn't think so since I don't
>remember hearing about it, and I know some programs don't break.)
>Is it done in each language?  For instance, does _main() in
>Sozobon C scan stdin for ^C and _exit() if it sees it?
>(I wouldn't think so since then everything would have to
>worry about it.)
>
Ctrl-C doesn't generate any special interrupt. The behavior of Ctrl-C
resides in the GEMDOS Cconin and Cconout routines. Thus, you can only
use Ctrl-C to terminate a program while it is reading or writing the
console.

>I'm asking because I'm toying with the idea of a vi-type
>Korn shell based on RTX.  I like gu:lam but I don't like microEmacs,
>and I miss multi-tasking and job control.  So, thinking about
>device drivers, SIGSTOP, and the like, I really should understand ^C.
>I suppose I could just have the cli slip in an isr to monitor
>whatever tty-type input devices, and grap any ^Z that comes along,
>but there'll probably be complications if I don't understand 
>what else is going on.
>
That sounds like the only way to do it.

>Or, does Dave Beckmyer's (sp?) shell have vi-like command line editing,
>and job control?  I haven't seen it, and from what I heard it's a C shell,
>but if it does have those other features I'd hate to re-invent the wheel.
>I've seen the RTX docs and have the highest respect for RTX's design
>(it reminds me of the kernel my OS Lab team did).

The manual for MT C Shell says there is full screen command-line editing.
It sounds pretty good. I haven't seen it yet, because the disk I received
was bad. The description of the built-in commands reads just like the BSD
C-Shell man page; most of the features are there. Unfortunately, unlike
the BSD shell, looping constructs are only usable in scripts. (So much for
aliases & such that do foreach and while loops...)

Meanwhile... Ctrl-C and Ctrl-Z are handled by the tty driver in Unix.
The MT C Shell manual makes no mention of using any special tty driver
with RTX. Wish I could run it right now and find out... (The disk is in
the mail?  }-)
--
  -- Howard Chu @ University of Michigan
  ... the glass is always greener on the side ...